Recently, a technology (e.g., a surgical apparatus) for integrating bone (bone tissue) and implant material made of biomedical material such as ceramics or composite material is being increasingly developed. When integrating the implant material and the bone, if even a slight change occurs in relative positions of the implant material and the bone during integration with each other, completion of the integration takes an extremely long time. Besides, if such a slight change is not detected and when the integration between the implant material and the bone is continued, the integration is finished while displacement is remained. Conventionally, to prevent occurrence of the slight change in the relative positions, a junction is fixed by a fixture that is rigid and heavy. Therefore, operation for integrating the implant material and the bone has been complicated and time-consuming.
Furthermore, to increase the strength of the integration between the implant material and the bone, the implant material and the bone are completely integrated with each other by using a metal bonding bolt, and thereafter, the bolt is removed. Accordingly, the integration between the implant material and the bone takes a long time, so that medical treatment for an affected area also takes a long time. Thus, a demand for integrating the bone and the implant material shortly and easily is growing.
Conventionally, to stabilize a relative position of implant material (surgical grafting material) to bone through promotion of bone bonding, the implant material is formed to have a textured surface so that bone tissue and the implant material can be integrated in a short time. For example, in an artificial hip composed of a femoral-sub-assembly to be fixed inside a femur of a patient and an acetabular-sub-assembly to be fixed inside an acetabulum of a patient, the femoral-sub-assembly includes an artificial stem having a textured surface or the like while the acetabular-sub-assembly includes an artificial cup having a textured surface or the like.
While the textured surface is formed to promote bone growth, because processes of (1) positioning, (2) immobilization with a cast, and (3) bone growth are necessary for integrating bone and implant material, a time as long as several months is sometimes necessary to achieve fixation (integration) as a complete recovery.
More particularly, Patent Document 1 discloses a laser processing method of providing a surface having undercut and mutual bonding recesses for making “scratch engagement” between implant material and bone easy, so that a time required for integrating the implant material and the bone is shortened with stabilized integration.
Furthermore, Paten Document 2 discloses a laser processing method of cutting dental tissue by applying a laser beam having a wavelength that can be intensively absorbed by hydroxylapatite. Moreover, Patent Document 3 discloses a laser processing method of removing mineralized physiological tissue including dental enamel, dentine, and bone by applying a laser beam having a wavelength that can be intensively absorbed by hydroxylapatite.
Furthermore, Patent Document 4 discloses a laser processing method of removing dental enamel and dentine by using a laser light having a wavelength of 2.0 μm to 3.0 μm. Moreover, Patent Document 5 discloses a laser processing method in which bone material, dental hard material, and arteriosclerotic deposit are peeled off by applying a laser having an emission wavelength of 9.6 μm.
Meanwhile, as a part of researches about implant material that can be easily and strongly integrated with bone, a technology for stabilizing a relative position of the implant material to bone by promoting bone bonding has been being developed. More particularly, a technology for porous biomedical material is expected to achieve preferable cell infiltration characteristic and being more increasingly studied.
The conventional research about the porous biomedical material includes a research about a spongelike structure that cannot retain inherent hardness of ceramics and a research about integration of a porous layer on base material, which leads to complicated fabricating process and variation in quality. The conventional research further includes a research about thermal spraying of apatite particles, which makes it difficult to control size of each hole to be formed, and a research about generation of texture only on the surface of ceramics without examining its internal structure. In addition, in the conventional laser processing methods, while a process for removing implant material or the like is performed, examination about surface modification has not been made at all.
More particularly, Patent Document 6 discloses a technology for setting carbonate apatite to be spongelike porous or spongelike super-porous and then compositing the carbonate apatite to collagen. Moreover, Patent Document 7 discloses a technology for using sponge containing hydroxylapatite and gel-like collagen as bone substitute in plastic surgery.
Furthermore, Patent Document 10 discloses a technology in which dense substrate and porous substrate are formed in separate processes, and then they are dried and sintered while being in contact with each other. Moreover, Patent Document 11 discloses a technology in which apatite particles are mixed dispersed in a glass layer, and after being baking, air holes are exposed by etching. Furthermore, Patent Document 12 discloses a technology for welding hydroxylapatite or tricalcium phosphate on the surface of base material by using plasma arc.
Patent Document 1: Japanese Patent Application Laid-open No. 2002-301091
Patent Document 2: Japanese Patent Application Laid-open No. H4-53550
Patent Document 3: Japanese Patent Application Laid-open No. H4-300535
Patent Document 4: Japanese Patent Application Laid-open No. H2-504478
Patent Document 5: Japanese Patent Application Laid-open No. S62-502170
Patent Document 6: Japanese Patent Application Laid-open No. 2003-169845
Patent Document 7: U.S. Pat. No. 5,071,436 Specification
Patent Document 8: U.S. Pat. No. 5,776,193 Specification
Patent Document 9: U.S. Pat. No. 6,187,047 Specification
Patent Document 10: Japanese Patent Application Laid-open No. S64-37475
Patent Document 11: Japanese Patent Application Laid-open No. H6-7425
Patent Document 12: Japanese Patent Application Laid-open No. S64-52471